This invention relates to a fuel sender assembly that includes an electrical fuel pump held in a mounting plate mounted in a fuel tank. More particularly, this invention relates to a fuel sender assembly where in the mounting plate mounts the fuel pump such that the fuel inlet to the fuel pump is disposed within the fuel tank and the electrical terminals for the fuel pump are accessible outside the fuel tank, and wherein a hermetic seal is formed between the mounting plate and the fuel pump to contain fuel vapors within the fuel tank.
In a typical automotive vehicle, fuel is supplied to an internal combustion engine from a fuel tank by a fuel sender assembly that includes an electric fuel pump mounted in the fuel tank. The electric fuel pump comprises electrical terminals connected to an external electrical system by wires within the fuel tank. There is concern that the wire insulation may become worn or damaged, or that the wires may become disconnected from the pump terminals, and that spurious sparking may occur. Under normal conditions, the fuel-rich vapors within the tank are deficient in oxygen and do not sustain combustion. Nonetheless, it is desired to prevent electrical sparking from contact with fuel vapors within the tank, as a precaution against even extraordinary circumstances that may arise, such as catastrophic breach of the fuel tank.
Therefore, it is desired to provide a fuel sender assembly that includes a fuel pump mounted in a fuel tank and wherein the electrical connections to the fuel pump are made directly to the fuel pump without wires within the fuel tank that may become worn or damaged or disconnected from pump terminals.
In accordance with a preferred embodiment of this invention, a fuel sender assembly is provided for use in a fuel tank, such as a fuel tank for an automotive vehicle. A fuel sender assembly includes a mounting plate adapted to be mounted in the fuel tank. The mounting plate includes a chamber wall that defines a pump chamber. The chamber wall has an inboard end disposed within the fuel tank and an outboard end, and extends circumferentially about the pump chamber between the ends. The fuel sender assembly also includes an electric fuel pump received in the pump chamber. The inlet end of the fuel pump, which includes the fuel inlet, is disposed within the fuel tank adjacent the inboard end of the pump chamber. The outlet end, which includes the electrical terminals for connection to an external power source, are disposed adjacent the outboard end of the pump chamber. The fuel sender assembly further comprises sealing means for forming a hermetic seal between the chamber wall and the fuel pump to prevent vapors from escaping from the fuel tank through the pump chamber. In one aspect of this invention, the seal is formed by a sealing element interposed between the housing of the fuel pump and the chamber wall. In another aspect of this invention, the mounting plate includes a circumferental projection that extends inwardly about the pump chamber adjacent the outboard end, and the seal is formed by a sealing element that engages the circumferential projection and the outlet end of the fuel pump. Accordingly, this invention provides a fuel sender assembly wherein the fuel pump is retained in a mounting plate that is attached to a fuel tank and wherein the electrical terminals are accessible outside the tank to allow them to be connected without requiring wires within the tank.